Physicists have devised a new experiment to test if the universe is a computer.

A philosophical thought experiment has long held that it is more likely than not that we're living inside a machine.

The theory basically goes that any civilisation which could evolve to a 'post-human' stage would almost certainly learn to run simulations on the scale of a universe. And that given the size of reality - billions of worlds, around billions of suns - it is fairly likely that if this is possible, it has already happened.

And if it has? Well, then the statistical likelihood is that we're located somewhere in that chain of simulations within simulations. The alternative - that we're the first civilisation, in the first universe - is virtually (no pun intended) absurd.

And it's not just theory. We previously reported that researchers at the University of Bonn in Germany had found evidence the Matrix was less than fiction. That story was by far our most popular of the year - indicating it's something about which you lot have wondered too.

Now another team have devised an actual test to see if this theory holds any hope of being proven.

Professor Martin Savage at the University of Washington says while our own computer simulations can only model a universe on the scale of an atom's nucleus, there are already "signatures of resource constraints" which could tell us if larger models are possible.

This is where it gets complex.

Essentially, Savage said that computers used to build simulations perform "lattice quantum chromodynamics calculations" - dividing space into a four-dimensional grid. Doing so allows researchers to examine the force which binds subatomic particles together into neutrons and protons - but it also allows things to happen in the simulation, including the development of complex physical "signatures", that researchers don't program directly into the computer. In looking for these signatures, such as limitations on the energy held by cosmic rays, they hope to find similarities within our own universe.

And if such signatures do appear in both? Boot up, baby. We're inside a computer. (Maybe).

"If you make the simulations big enough, something like our universe should emerge," Savage told the University of Washington news service.

Zohreh Davoudi, one of Savage's students, goes further:

"The question is, 'Can you communicate with those other universes if they are running on the same platform?," she said.

Physicists say they may have evidence that the universe is a computer simulation.

How? They made a computer simulation of the universe. And it looks sort of like us.

A long-proposed thought experiment, put forward by both philosophers and popular culture, points out that any civilisation of sufficient size and intelligence would eventually create a simulation universe if such a thing were possible.

And since there would therefore be many more simulations (within simulations, within simulations) than real universes, it is therefore more likely than not that our world is artificial.

Now a team of researchers at the University of Bonn in Germany led by Silas Beane say they have evidence this may be true.

In a paper named 'Constraints on the Universe as a Numerical Simulation', they point out that current simulations of the universe - which do exist, but which are extremely weak and small - naturally put limits on physical laws.

Technology Review explains that "the problem with all simulations is that the laws of physics, which appear continuous, have to be superimposed onto a discrete three dimensional lattice which advances in steps of time."

What that basically means is that by just being a simulation, the computer would put limits on, for instance, the energy that particles can have within the program.

These limits would be experienced by those living within the sim - and as it turns out, something which looks just like these limits do in fact exist.

For instance, something known as the Greisen-Zatsepin-Kuzmin, or GZK cut off, is an apparent boundary of the energy that cosmic ray particles can have. This is caused by interaction with cosmic background radiation. But Beane and co's paper argues that the pattern of this rule mirrors what you might expect from a computer simulation.

Naturally, at this point the science becomes pretty tricky to wade through - and we would advise you read the paper itself to try and get the full detail of the idea.

But the basic impression is an intriguing one.

Like a prisoner in a pitch-black cell, we may never be able to see the 'walls' of our prison -- but through physics we may be able to reach out and touch them.